ADVENTRX COMPLETES ACQUISITION OF SYNTHRX SAN DIEGO (

ADVENTRX COMPLETES ACQUISITION OF SYNTHRX

SAN DIEGO (April 11, 2011) ADVENTRX Pharmaceuticals, Inc. (NYSE Amex: ANX) today

announced that it has completed its acquisition of SynthRx, Inc., now a wholly owned subsidiary of

ADVENTRX. SynthRx s lead product candidate is a novel, proprietary, rheologic and antithrombotic

compound, poloxamer 188, that ADVENTRX will develop as ANX-188.

With ANX-188, we add to our pipeline another late-stage asset with multiple exciting development

opportunities. We plan to meet with FDA this year to reach agreement on a protocol for a pivotal

phase 3 study for treatment of sickle cell crisis in a pediatric population, an orphan indication,

said Brian M. Culley, Chief Executive Officer of ADVENTRX. Because sickle cell crisis is a severe

and painful condition often with life-threatening complications and for which existing drugs

provide only limited symptomatic relief, there is a significant need to improve treatment options.

Beyond sickle cell, ANX-188 may have clinical utility in other acute events related to

microvascular-flow abnormalities, such as heart attack, stroke and hemorrhagic shock.

As previously announced, ADVENTRX and SynthRx entered into a definitive merger agreement in

February 2011, which was completed on April 8, 2011. In connection with the closing, ADVENTRX

issued approximately 2.8 million shares of its common stock, of which 862,078 shares (or an

approximately 3.3% ownership stake) are vested and approximately 1.9 million are unvested. The

unvested shares will vest upon dosing of the first patient in a phase 3 clinical study meeting

certain criteria, subject to reductions based on the timing of dosing of the first patient and the

anticipated size of the study. SynthRx stockholders also are entitled to receive additional shares

of common stock upon successful achievement of development milestones consisting of dosing of the

first patient in a phase 3 clinical study meeting certain criteria (subject to reduction as

described above), acceptance by the U.S. Food and Drug Administration (FDA) of a New Drug

Application (NDA) and approval by the FDA of an NDA. Of the total shares issuable in connection

with the acquisition, more than 75% are contingent upon the FDA accepting and approving an NDA

covering ANX-188 to treat sickle cell crisis in children.

Should ADVENTRX s stockholders not approve the issuance of the milestone-related shares as required

by NYSE Amex listing standards, ADVENTRX would pay SynthRx s stockholders in cash the value of the

shares it otherwise would have issued, with the NDA acceptance and NDA approval milestone payments

payable based on net sales of ANX-188 and all milestone payments payable in quarterly installments.

The investment banking firm Canaccord Genuity Inc. advised ADVENTRX and its Board of Directors in

connection with the transaction. Beal Advisors advised SynthRx.

About ADVENTRX Pharmaceuticals

ADVENTRX Pharmaceuticals is a specialty pharmaceutical company focused on acquiring, developing and

commercializing proprietary product candidates. More information can be found on the Company s web

site at www.adventrx.com.

Forward Looking Statements

ADVENTRX cautions you that statements included in this press release that are not a description of

historical facts are forward-looking statements that are based on ADVENTRX s current expectations

and assumptions. Such forward-looking statements include, but are not limited to, statements

regarding development opportunities and plans for ANX-188 and their timing, ANX-188 s ability to

demonstrate clinical benefits for patients suffering from sickle cell crisis and other

microvascular-flow abnormalities and the form of consideration payable to SynthRx s stockholders.

Actual events or results may differ materially from those expressed or implied by the

forward-looking statements in this press release due to a number of risks and uncertainties,

including, without limitation: delays associated with the development of ANX-188, including

identifying and qualifying contract manufacturers and contract research organizations and developing and reaching agreement with FDA

regarding a pivotal phase 3 clinical study, including the potential for FDA to require additional

nonclinical or clinical work prior to initiating the currently contemplated phase 3 clinical trial

of ANX-188; the potential that the cost and time required to develop ANX-188 are greater than

ADVENTRX s current expectations; the risk that clinical study results do not support the safety and

efficacy or the commercial viability of ANX-188; the potential that ADVENTRX s stockholders do not

approve the issuance of the milestone-related shares and ADVENTRX must pay the cash value of those

shares, to the extent the milestones are achieved; the risk that ADVENTRX may not be able to

integrate SynthRx s assets successfully into its operations or that it may incur unexpected costs

and disruptions to its business as a result of such integration; the risk that the neither the FDA

nor any other regulatory agency approves a product based on ANX-188 or any other product candidate

developed using technology acquired from SynthRx on a timely basis, or at all; the potential that

ADVENTRX may require substantial additional funding to develop and commercialize ANX-188, and the

risk that ADVENTRX may not be able to raise sufficient capital when needed, or at all; and other

risks and uncertainties more fully described in ADVENTRX s press releases and periodic filings with

the Securities and Exchange Commission. ADVENTRX s public filings with the Securities and Exchange

Commission are available at www.sec.gov.

You are cautioned not to place undue reliance on forward-looking statements, which speak only as of

the date when made. ADVENTRX does not intend to revise or update any forward-looking statement set

forth in this press release to reflect events or circumstances arising after the date hereof,

except as may be required by law.